This is a revised proposal to implement and test a portable, low-cost ultrasound/computer system for epidemiological screening of carotid intima-media thickness (IMT). The system will consist of an integrated ultrasound scanner and PC computer system with the capability: 1) to acquire and store ultrasound images using computer-assisted methods to replicate transducer position on serial examinations, 2) to measure IMT from on-line digitized images or from images recorded on video tape and then digitized, and 3) to store and retrieve patient records and images on transportable media. The system will consist of an ATL Ultramark 4B-mode ultrasound scanner interfaced to a PC computer with all components packaged into two small carts. The IMT measurement method will utilize the automated echo- tracking method jointly developed by the Jet Propulsion Laboratory (JPL) and the University of Southern California (USC) which has the capability to reduce measurement variability more than 70 percent when compared to existing IMT assessment techniques based on manual boundary identification. The reproducibility of common carotid IMT measurements from images acquired with unassisted transducer positioning will be compared to that from images acquired with three computer-assisted transducer positioning techniques. The inter- and intrasonographer variability for the most reproducible transducer positioning method will be determined from replicate scans on 100 subjects. Subjects in the reproducibility assessment will be selected to exhibit a wide range of wall thicknesses in order to determine any possible association between measurement variability and degree of wall thickening. The performance of the system using the ATL Ultramark 4 ultrasound scanner will be compared to that using a non-portable Toshiba SSH140 ultrasound system which has been in use in clinical use for IMT measurement in the USC Atherosclerosis Research Unit.